Leerink analyst Geoffrey Porges says Medivation's stock has come under significant pressure following an open letter from several U.S. representatives calling for the National Institutes of Health to exercise its "march-in" rights to mandatorily lower the price of Xtandi. However, the analyst believes the letter will have "virtually no chance" of any material change in the realized price for the drug, adding that he sees no reason to change his outlook for Xtandi, or Medivation. Porges reiterates his Market perform rating and $39 price target on Medivation's shares.